Flaviviruses (FVs) are a very heterogeneous group of viruses that includes viruses capable of infecting insects and/or vertebrates. Different human-disease-causing FVs are disseminated by mosquitoes, and therefore, the search for FV in these insects has recently been proposed in order to evaluate their potential transmission in a given community. An entomological survey was carried out in Colima (the hyperendemic dengue fever transmission zone in Mexico) to collect culicidae in urban and wild areas. No human-pathogenic FVs were found, but sequences related to a potentially novel strain of cell fusing agent virus (CFAV) were detected in Stegomyia (Aedes) aegypti mosquitoes.